I get that people go on about youth and speed on the bike.

It still seems to me a lot of it has to do with free time.

Young kids who recover well and use their infinite free time will be fast. So will middle aged guys whose kids left the house already and have built up 5 weeks of vacation at work.

Edge to the recovery of the youth, but often the fastest triathlon and duathlon age group is the 35 to 45 range.

I did a local du and missed the podium due to the birthday bump. I was 34 to be 35 months later. The 35 to 45 AG took 1/2/3 overall in the entire event and in the AG. I would have won the younger AG.